[lld] Fix .bss section accumulated in ELF file (PR #78265)
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Tue Jan 16 05:42:23 PST 2024
https://github.com/deepa2015 updated https://github.com/llvm/llvm-project/pull/78265
>From 03a4c4e5f150ab9215ccc817b950f39c96c1ecdb Mon Sep 17 00:00:00 2001
From: Shivaprasad Moodalappa <Shivaprasad.Moodalappa at windriver.com>
Date: Tue, 16 Jan 2024 04:05:53 -0800
Subject: [PATCH 1/2] Fix .bss section accumulated in ELF file
---
lld/ELF/Writer.cpp | 12 +++++++---
lld/ELF/Writer.h | 3 ++-
lld/test/ELF/linkerscript/sections-nonalloc.s | 22 +++++++++----------
lld/test/ELF/linkerscript/sections.s | 6 ++---
lld/test/ELF/x86-64-section-layout.s | 10 ++++-----
5 files changed, 30 insertions(+), 23 deletions(-)
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index dfec5e07301a74a..59c240a0c893b05 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -2630,16 +2630,22 @@ static uint64_t computeFileOffset(OutputSection *os, uint64_t off) {
// increasing rather than setting to zero.
if (os->type == SHT_NOBITS &&
(!Out::tlsPhdr || Out::tlsPhdr->firstSec != os))
- return off;
+ {
+ // Update no_bits size in the current segment
+ if (os->ptLoad)
+ os->ptLoad->p_nobits += os->size;
+ return off;
+ }
// If the section is not in a PT_LOAD, we just have to align it.
if (!os->ptLoad)
return alignToPowerOf2(off, os->addralign);
// If two sections share the same PT_LOAD the file offset is calculated
- // using this formula: Off2 = Off1 + (VA2 - VA1).
+ // using this formula: Off2 = Off1 + (VA2 - VA1 - p_nobits).
OutputSection *first = os->ptLoad->firstSec;
- return first->offset + os->addr - first->addr;
+
+ return first->offset + (os->addr - first->addr - os->ptLoad->p_nobits);
}
template <class ELFT> void Writer<ELFT>::assignFileOffsetsBinary() {
diff --git a/lld/ELF/Writer.h b/lld/ELF/Writer.h
index aac8176d90989f3..6f5ab6ce3202f26 100644
--- a/lld/ELF/Writer.h
+++ b/lld/ELF/Writer.h
@@ -37,7 +37,8 @@ struct PhdrEntry {
uint32_t p_align = 0;
uint32_t p_type = 0;
uint32_t p_flags = 0;
-
+ // NO_BITS size processed in the output section..
+ uint64_t p_nobits =0;
OutputSection *firstSec = nullptr;
OutputSection *lastSec = nullptr;
bool hasLMA = false;
diff --git a/lld/test/ELF/linkerscript/sections-nonalloc.s b/lld/test/ELF/linkerscript/sections-nonalloc.s
index a0669f701d8c90c..03de378c3b2a4c3 100644
--- a/lld/test/ELF/linkerscript/sections-nonalloc.s
+++ b/lld/test/ELF/linkerscript/sections-nonalloc.s
@@ -37,18 +37,18 @@
# CHECK1-NEXT: [ 0] NULL 0000000000000000 000000 000000 00 0
# CHECK1-NEXT: [ 1] .text PROGBITS 00000000000000b0 0000b0 000001 00 AX 0
# CHECK1-NEXT: [ 2] .bss NOBITS 00000000000000b1 0000b1 000001 00 WA 0
-# CHECK1-NEXT: [ 3] data1 PROGBITS 00000000000000b2 0000b2 000001 00 WA 0
-# CHECK1-NEXT: [ 4] data3 PROGBITS 00000000000000b3 0000b3 000001 00 WA 0
-# CHECK1-NEXT: [ 5] other1 PROGBITS 0000000000000000 0000b8 000001 00 0
-# CHECK1-NEXT: [ 6] other2 PROGBITS 0000000000000000 0000c0 000001 00 0
-# CHECK1-NEXT: [ 7] other3 PROGBITS 0000000000000000 0000d0 000001 00 0
-# CHECK1-NEXT: [ 8] .symtab SYMTAB 0000000000000000 0000d8 000030 18 10
-# CHECK1-NEXT: [ 9] .shstrtab STRTAB 0000000000000000 000108 00004d 00 0
-# CHECK1-NEXT: [10] .strtab STRTAB 0000000000000000 000155 000008 00 0
-# CHECK1-NEXT: [11] data2 PROGBITS 00000000000000b4 0000b4 000001 00 WA 0
+# CHECK1-NEXT: [ 3] data1 PROGBITS 00000000000000b2 0000b1 000001 00 WA 0
+# CHECK1-NEXT: [ 4] data3 PROGBITS 00000000000000b3 0000b2 000001 00 WA 0
+# CHECK1-NEXT: [ 5] other1 PROGBITS 0000000000000000 0000b4 000001 00 0
+# CHECK1-NEXT: [ 6] other2 PROGBITS 0000000000000000 0000b8 000001 00 0
+# CHECK1-NEXT: [ 7] other3 PROGBITS 0000000000000000 0000c0 000001 00 0
+# CHECK1-NEXT: [ 8] .symtab SYMTAB 0000000000000000 0000c8 000030 18 10
+# CHECK1-NEXT: [ 9] .shstrtab STRTAB 0000000000000000 0000f8 00004d 00 0
+# CHECK1-NEXT: [10] .strtab STRTAB 0000000000000000 000145 000008 00 0
+# CHECK1-NEXT: [11] data2 PROGBITS 00000000000000b4 0000b3 000001 00 WA 0
# CHECK1: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
-# CHECK1-NEXT: LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x0000b5 0x0000b5 RWE 0x1000
-# CHECK1-NEXT: 0x60000000 0x0000b8 0x0000000000000000 0x0000000000000000 0x000009 0x000001 0x8
+# CHECK1-NEXT: LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x0000b4 0x0000b5 RWE 0x1000
+# CHECK1-NEXT: 0x60000000 0x0000b4 0x0000000000000000 0x0000000000000000 0x000005 0x000001 0x8
#--- a.lds
SECTIONS {
diff --git a/lld/test/ELF/linkerscript/sections.s b/lld/test/ELF/linkerscript/sections.s
index 539aa9c1705888b..6ac435f74b99739 100644
--- a/lld/test/ELF/linkerscript/sections.s
+++ b/lld/test/ELF/linkerscript/sections.s
@@ -79,12 +79,12 @@
# SEP-BY-NONALLOC: [ 1] .text PROGBITS 0000000000000000 001000 00000e 00 AX
# SEP-BY-NONALLOC-NEXT: [ 2] .data PROGBITS 000000000000000e 00100e 000020 00 WA
# SEP-BY-NONALLOC-NEXT: [ 3] .bss NOBITS 000000000000002e 00102e 000002 00 WA
-# SEP-BY-NONALLOC-NEXT: [ 4] .comment PROGBITS 0000000000000000 001033 000008 01 MS
-# SEP-BY-NONALLOC: [ 8] other PROGBITS 0000000000000030 001030 000003 00 WA
+# SEP-BY-NONALLOC-NEXT: [ 4] .comment PROGBITS 0000000000000000 001031 000008 01 MS
+# SEP-BY-NONALLOC: [ 8] other PROGBITS 0000000000000030 00102e 000003 00 WA
# SEP-BY-NONALLOC: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
# SEP-BY-NONALLOC-NEXT: LOAD 0x001000 0x0000000000000000 0x0000000000000000 0x00000e 0x00000e R E 0x1000
-# SEP-BY-NONALLOC-NEXT: LOAD 0x00100e 0x000000000000000e 0x000000000000000e 0x000025 0x000025 RW 0x1000
+# SEP-BY-NONALLOC-NEXT: LOAD 0x00100e 0x000000000000000e 0x000000000000000e 0x000023 0x000025 RW 0x1000
# SEP-BY-NONALLOC-NEXT: GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW 0
# Input section pattern contains additional semicolon.
diff --git a/lld/test/ELF/x86-64-section-layout.s b/lld/test/ELF/x86-64-section-layout.s
index 37201279fa0a5d0..9d60510a0d13b65 100644
--- a/lld/test/ELF/x86-64-section-layout.s
+++ b/lld/test/ELF/x86-64-section-layout.s
@@ -57,17 +57,17 @@
# CHECK2-NEXT: .tbss.1 NOBITS 0000000000200307 000306 000001 00 WAT 0 0 1
# CHECK2-NEXT: .data PROGBITS 0000000000200306 000306 000001 00 WA 0 0 1
# CHECK2-NEXT: .bss NOBITS 0000000000200307 000307 001800 00 WA 0 0 1
-# CHECK2-NEXT: .ldata PROGBITS 0000000000201b07 001b07 000002 00 WAl 0 0 1
-# CHECK2-NEXT: .ldata2 PROGBITS 0000000000201b09 001b09 000001 00 WAl 0 0 1
-# CHECK2-NEXT: .lbss NOBITS 0000000000201b0a 001b0a 000002 00 WAl 0 0 1
-# CHECK2-NEXT: .comment PROGBITS 0000000000000000 001b0a {{.*}} 01 MS 0 0 1
+# CHECK2-NEXT: .ldata PROGBITS 0000000000201b07 000307 000002 00 WAl 0 0 1
+# CHECK2-NEXT: .ldata2 PROGBITS 0000000000201b09 000309 000001 00 WAl 0 0 1
+# CHECK2-NEXT: .lbss NOBITS 0000000000201b0a 00030a 000002 00 WAl 0 0 1
+# CHECK2-NEXT: .comment PROGBITS 0000000000000000 00030a {{.*}} 01 MS 0 0 1
# CHECK2: Program Headers:
# CHECK2-NEXT: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
# CHECK2-NEXT: PHDR 0x000040 0x0000000000200040 0x0000000000200040 {{.*}} {{.*}} R 0x8
# CHECK2-NEXT: LOAD 0x000000 0x0000000000200000 0x0000000000200000 0x000304 0x000304 R 0x1000
# CHECK2-NEXT: LOAD 0x000304 0x0000000000200304 0x0000000000200304 0x000001 0x000001 R E 0x1000
-# CHECK2-NEXT: LOAD 0x000305 0x0000000000200305 0x0000000000200305 0x001805 0x001807 RW 0x1000
+# CHECK2-NEXT: LOAD 0x000305 0x0000000000200305 0x0000000000200305 0x000005 0x001807 RW 0x1000
# CHECK2-NEXT: TLS 0x000305 0x0000000000200305 0x0000000000200305 0x000001 0x000003 R 0x1
#--- a.s
>From d8c660717fabf7b685d0eec09e481dc09bfbca2d Mon Sep 17 00:00:00 2001
From: Shivaprasad Moodalappa <Shivaprasad.Moodalappa at windriver.com>
Date: Tue, 16 Jan 2024 05:41:58 -0800
Subject: [PATCH 2/2] Fix format-style issues
---
lld/ELF/Writer.cpp | 9 ++++-----
lld/ELF/Writer.h | 2 +-
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 59c240a0c893b05..c7dab085c845688 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -2629,17 +2629,16 @@ static uint64_t computeFileOffset(OutputSection *os, uint64_t off) {
// in a PT_LOAD/PT_TLS. By convention, we keep section offsets monotonically
// increasing rather than setting to zero.
if (os->type == SHT_NOBITS &&
- (!Out::tlsPhdr || Out::tlsPhdr->firstSec != os))
- {
- // Update no_bits size in the current segment
+ (!Out::tlsPhdr || Out::tlsPhdr->firstSec != os)) {
+ // Update NOBITS size in the current segment
if (os->ptLoad)
- os->ptLoad->p_nobits += os->size;
+ os->ptLoad->p_nobits += os->size;
return off;
}
// If the section is not in a PT_LOAD, we just have to align it.
if (!os->ptLoad)
- return alignToPowerOf2(off, os->addralign);
+ return alignToPowerOf2(off, os->addralign);
// If two sections share the same PT_LOAD the file offset is calculated
// using this formula: Off2 = Off1 + (VA2 - VA1 - p_nobits).
diff --git a/lld/ELF/Writer.h b/lld/ELF/Writer.h
index 6f5ab6ce3202f26..df3640c03595b77 100644
--- a/lld/ELF/Writer.h
+++ b/lld/ELF/Writer.h
@@ -38,7 +38,7 @@ struct PhdrEntry {
uint32_t p_type = 0;
uint32_t p_flags = 0;
// NO_BITS size processed in the output section..
- uint64_t p_nobits =0;
+ uint64_t p_nobits = 0;
OutputSection *firstSec = nullptr;
OutputSection *lastSec = nullptr;
bool hasLMA = false;
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